I looked at the mountainous (seems like it on maps) region between Escondido and Temecula.
That doesn't look like suburbs, although there are a handful of housing developments. But these are not in the outskirts of an urban area like a suburb, these are more rural and not attached to any city.
Yes, sure, once you go outside cities into semi-rural or rural regions, it's easy to be way more than 5 miles from shopping.